Arthritis mutilans is the most severe form of psoriatic arthritis (PsA). About 5 percent of people with PsA develop this rare disorder, which causes deformities and dysfunction primarily in the small joints of the fingers and toes, according to the National Psoriasis Foundation. In rare cases, arthritis mutilans can also occur in people with rheumatoid arthritis.
Alongside common PsA symptoms — including stiff joints and decreased range of motion — osteolysis (bone loss) is a key feature of arthritis mutilans. Osteolysis causes a dramatic deformity of the fingers and toes, making it hard to straighten or bend a joint.
Early diagnosis and treatment of arthritis mutilans is critical to limiting or stopping disease progression, which can permanently damage or destroy your joints. Delaying a visit with a rheumatologist for more than six months after symptoms first appear can worsen long-term outcomes.
Of the five forms of psoriatic arthritis, arthritis mutilans is the most aggressive and advanced type. Although its cause is not known, arthritis mutilans typically occurs when the immune system mistakenly attacks healthy cells in joints. The resulting inflammation causes bone tissue to break down and be reabsorbed into the body.
People with PsA who aren’t currently in treatment — or whose condition has been unresponsive to treatment — are at the highest risk of developing arthritis mutilans. Having a family history of psoriasis or PsA is also a risk factor. About 40 percent of people with PsA, for example, have a family member with psoriasis or arthritis, suggesting a genetic link.
Unlike rheumatoid arthritis, which affects both sides of the body, arthritis mutilans usually appears in an asymmetric pattern on one side of the body. It typically affects the small bones of the hands and feet — specifically, the distal interphalangeal joint (at the end of the fingers), metacarpophalangeal (knuckle) joint in the hands, and metatarsophalangeal joints (“toe knuckles”) in the feet. Classic symptoms of arthritis mutilans include telescoping fingers and pencil-in-cup deformity.
Arthritis mutilans starts with severe inflammation that makes it hard to bend and straighten your joints. You may have trouble making a tight fist or doing activities such as buttoning a shirt or cooking a meal. Arthritis mutilans is often a progression of psoriatic arthritis, especially when treatment wasn’t used or didn’t work.
Sometimes referred to as “opera-glass hands,” a symptom called “telescoping fingers” occurs when connective tissues can’t support the joints in fingers, causing them to shorten or bunch together. Pulling on fingers may cause them to lengthen or open up like a pair of opera glasses. The joints may flail in unusual directions. Collapsed digits can also lead to excess skin that appears folded like a telescope.
Severe joint erosion typical of arthritis mutilans causes pencil-in-cup deformity. The end of a bone in a finger narrows like a pencil point, while the top of the neighboring bone erodes into a cuplike shape. This damage is typically seen with an X-ray.
Telescoping and pencil-in-cup deformities can also affect the toes and mobility. Exercise is important to maintain flexibility, and sometimes orthopedic inserts or a walking aid can help prevent further stress and damage to lower extremities. Stationary cycling and water aerobics are also good options for people with foot issues from arthritis mutilans.
Other symptoms of arthritis mutilans include ankylosis (fused joints) and loss of range of motion.
A 2015 systematic review of current research on arthritis mutilans found that the condition is a polyarthritis disease — most people who developed it had multiple affected joints. In a 2017 Scandinavian study of 67 people with arthritis mutilans, the average number of damaged joints per person was 8.2.
Although psoriatic arthritis rarely becomes arthritis mutilans, when it does, the progression can be rapid. Arthritis mutilans could occur within a few months or up to several years after the onset of PsA.
Less commonly, arthritis mutilans has been associated with axial spondyloarthritis — a chronic, inflammatory disease of the spine and sacroiliac joints (joints that connect the pelvis to the spine). This can lead to sacroiliitis (inflammation) where the lower spine meets the pelvis. While not a classic arthritis mutilans symptom, sacroiliitis is present in many people with arthritis mutilans.
Because psoriatic arthritis mutilans and rheumatoid arthritis have similar symptoms, a diagnosis can be mistaken or delayed. Diagnosis is typically based on a family history of psoriasis, genetic markers, and the presence of such PsA symptoms as dactylitis (“sausage” fingers or toes) and enthesitis (inflammation of tendons and ligaments that attach to bone).
A rheumatologist will first perform a physical exam to confirm the type of arthritis, checking joints for swelling or tenderness. A blood test can detect certain antibodies or rheumatoid factor, which would indicate rheumatoid arthritis. Diagnosis also involves radiographic imaging (X-rays) to investigate the type and degree of bone loss.
No medicines have been specifically approved for treating arthritis mutilans. It’s still important to seek treatment as early as possible, as there are many options for managing symptoms and slowing disease progression. Depending on the severity of the disease and joint destruction, rheumatologists may prescribe one or more of the following treatments commonly used for people with psoriatic arthritis.
Guidelines developed by the National Psoriasis Foundation and the American College of Rheumatology currently recommend biologic drugs as the first-line treatment for severe PsA. Biologics are either injected or given by IV. They’re usually taken long-term as maintenance drugs to prevent disease flares and progression. Biologics can reduce inflammation and protect joints, but they don’t reverse joint damage and deformity.
Tumor necrosis factor (TNF) inhibitors, one class of biologics, are treatments for severe PsA that hasn’t responded to other therapies. TNF inhibitors are often highly effective at treating a wide range of PsA symptoms, including those in arthritis mutilans.
Adalimumab (Humira) is one of the most commonly prescribed TNF inhibitors for PsA. Others include:
Newer biologics approved for psoriatic arthritis, including arthritis mutilans, stop inflammation by inhibiting certain functions in the body. They include:
Disease-modifying antirheumatic drugs (DMARDs) are systemic drugs prescribed for moderate to severe PsA, including arthritis mutilans. They can affect the disease course by reducing joint and tissue damage, slowing disease progression, and relieving symptoms.
Methotrexate (sold under several brand names, including Trexall), is most commonly prescribed for arthritis mutilans. It’s sometimes used in combination with a TNF inhibitor.
Read more about treatments for psoriatic arthritis, including details about biologic DMARDs and side effects.
Nonsteroidal anti-inflammatory drugs (NSAIDs) are typically used to manage symptoms of psoriatic arthritis, including arthritis mutilans. NSAIDs can reduce swelling and pain, making it easier to walk and move, but they don’t limit disease progression or joint damage. Popular over-the-counter NSAIDs for arthritis mutilans include:
Long-term use of NSAIDs can cause side effects, including stomach problems such gastrointestinal bleeding and ulcers.
Also known as steroids, corticosteroids may be injected into joints to reduce ongoing inflammation in people with arthritis mutilans. Injections allow doctors to deliver a higher dose than is possible with oral medications.
Long-term use of steroids can increase joint damage, as well as the risk of infection, bone fractures, and chronic diseases such as osteoporosis, high blood pressure, obesity, diabetes, and heart disease.
To help delay the progression of arthritis mutilans, rheumatologists recommend early and aggressive physical and occupational therapy. Hand therapy is particularly important because it strengthens muscles around the joints, improving dexterity and overall use of fingers and hands.
Joint-replacement surgery, bone grafts, or arthrodesis (joint fusion) may be an option for severely damaged joints. These procedures can help relieve symptoms, restore some function, and improve quality of life with arthritis mutilans. Surgery should be considered a last resort because it typically requires downtime for recovery, and there are risks of infection.
Arthritis mutilans can have a significant impact on quality of life. In the Scandinavian study of people with arthritis mutilans, 42 percent retired early or took sick leave, while 21 percent could not care for themselves on a daily basis.
With good self-care, however, it’s possible to reduce symptoms, improve functioning in hands and feet, and boost overall health and well-being. Strategies such as the following can help put the brakes on inflammation and make you more responsive to treatment:
Complementary therapies, such as meditation, acupuncture, and stress management techniques, have helped some people better manage the pain and symptoms of psoriatic disease, including arthritis mutilans.
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